It's always good to update, with any update its fine to wait a couple days, woocommerce often updates then follows with a bug fix update a day later. So it's fine to wait a little to update but it's good to keep up with updates. And you should always update the theme if you update woocommerce.

It doesn't matter if you are using a child theme when you update the plugin, just beware that if your child theme has woocommerce template files you will need to update those.